Answer:
8 Joule
Step-by-step explanation:
Mass of block = 2 kg
Displacement = x = 800 mm = 0.8 m
Spring constant = k = 25 N/m
Potential Energy of a spring
Work done = Difference in Potential Energy
Work Done = Δ P.E.

⇒P.E. = 0.5×25×0.8²
⇒P.E. = 8 Nm = 8 Joule
Here already the spring constant and displacement is given so the mass will not be used while calculating the potential energy.
Answer:
B
Step-by-step explanation:
B
Answer:
6.75
Step-by-step explanation:
h=hat, s=scarf
5h + 1s = $47 (equation 1)
2h + 2s = $40 (equation 2)
multiply equation 1 by 2 , we get: 10h + 2s = $94 (equation 3)
equation 3 minus equation 2, we get:
8h = $54 ⇒ h = $6.75 ⇔ 1 hat cost $6.75
substitute h = $6.75 into equation 2 to find s,
2($6.75) + 2s = $40
$13.5 + 2s = $40
2s = $26.5
s = $13.25 ⇔ 1 scarf cost $13.25
Fraction is used to rename 5/6
the answer os 5xx entendida